Skeleton structural member for transportation equipment

ABSTRACT

A skeleton structure member made up of a skeleton member ( 11 ) having a cross-sectionally closed space ( 16, 33, 43, 63, 73, 83, 93 ) and multiple granules ( 17 ) packed inside the skeleton member. A granule flow allowing part ( 14, 42, 61, 71, 81, 92 ) for allowing movement of the multiple granules is provided inside the skeleton member and suppresses excessive rising of internal pressure within the skeleton member. The granule flow allowing part is provided in the vicinity of the multiple granules.

TECHNICAL FIELD

This invention relates to a skeleton structure member for use in atransport machine such as a railroad car, an industrial vehicle, a ship,an aircraft, an automobile or a motorcycle.

BACKGROUND ART

Skeleton structure members made by filling a skeleton member with agranular bulk material are known from for example JP-A-2002-193649, U.S.Pat. No. 4,610,836 and U.S. Pat. No. 4,695,343. Also, skeleton structuremembers made by filling a skeleton member with a gel are known from forexample JP-A-9-136681.

FIG. 13 shows a solidified granular bulk material of a skeletonstructure member disclosed in JP-A-2002-193649.

As shown in FIG. 13, the solidified granular bulk material 200 is madeup of multiple granules 201 and a binder 202 consisting of a resin or anadhesive packed between the granules 201 to solidify the granules 201,whereby the granules 201 are bonded together into a solid. The granules201 are packed into a mold in a dense state, and then the binder 202 ispoured in to form the solidified granular bulk material 200. Thissolidified granular bulk material 200 is inserted into a skeleton memberof a vehicle body or the like to make a skeleton structure member, andthe strength and rigidity of the vehicle body is thereby raised.

FIG. 14 shows a solidified granular bulk material of a skeletonstructure member set forth in U.S. Pat. No. 4,610,836 and U.S. Pat. No.4,695,343.

This solidified granular bulk material 210 made by bonding together andthereby solidifying multiple granules for insertion into a skeletonmember is made up of multiple small glass spheres 212 serving asgranules coated with an adhesive 211. These glass spheres 212 arewrapped with a cloth made of glass fiber and packed into a skeletonmember to make a skeleton structure member.

FIG. 15 shows a skeleton structure member disclosed in JP-A-9-136681.This skeleton structure member 220 has a gel 223 packed between twolower panels 221, 222. The reference number 224 denotes an orificeprovided in the lower panel 222, and 225 a cap for plugging the orifice224.

For example when in a vehicle collision or the like an excessivepressure arises in the gel 223, the cap 225 comes out under thatpressure and allows the gel 223 to spurt out, whereby impact energy isabsorbed.

A crush test method for applying a load to and forcibly breaking askeleton structure member and results of crush tests carried out by thismethod on the skeleton structure members of related art shown in FIG. 13to FIG. 15 are shown below.

FIG. 16 and FIG. 17 show details of the crush tests carried out on theskeleton structure members of related art, FIG. 16 illustrating thecrushing and FIG. 17 being a graph showing the results of the crushtests.

In FIG. 16A, a skeleton structure member 232 made by filling a skeletonmember 231 having a hollow square cross-section with granules isforcibly deformed by a compressive load F being applied to it in thelength direction as shown with an arrow.

In FIG. 16B, when the deformation of the skeleton structure member 232,and specifically the displacement of the end of the skeleton structuremember 232 under the load, is written λ, as the displacement λ increasesthe skeleton structure member 232 either buckles into a bellows shape orbends into a Z shape like that shown in the figure or into a dog-legshape.

FIG. 17 is a graph showing the relationship between the load F and thedisplacement λ of the skeleton structure member when it is deformed asshown in FIG. 16B. The vertical axis shows the load F and the horizontalaxis the displacement λ. Four test pieces were used: Comparison Example1 (unfilled), which was a skeleton member only, not packed with anyfiller; Comparison Example 2 (granules bonded with binder), which wasthat shown in FIG. 13 made by bonding granules with a binder; ComparisonExample 3 (small spheres bonded with adhesive), which was that shown inFIG. 14 made by bonding small spheres with an adhesive; and ComparisonExample 4 (low-strength granules) filled with a granules of lowerstrength than Comparison Example 2 and Comparison Example 3.

In Comparison Example 1, the load F is small but the displacement λ atwhich the skeleton member collapses into a bellows shape is large. Thedisplacement d1 at this time is the displacement at which the skeletonmember collapses completely, and is the effective stroke (that is, thedisplacement λ from zero to d1) over which energy applied from outsidecan be absorbed effectively. After this effective stroke the load Fincreases sharply.

Comparison Example 2 to Comparison Example 4 are shown as far as theireffective strokes.

The area in the effective stroke region sandwiched between the line ofComparison Example 1 and the horizontal axis shows the energy absorbedby the skeleton structure member of Comparison Example 1, and the valueobtained by dividing this absorbed energy by the effective stroke is theload f1 in the figure. That is, this load f1 is the average load in ofExample 1.

From this, to increase the energy absorbed by a skeleton structuremember, a high average load and a long effective stroke are necessary.

In Comparison Example 2 (granules bonded with a binder, described withreference to FIG. 13), the average load is very large but thedisplacement λ is not so large. This is because, since the bonding ofthe granules is extremely strong, in the initial stage of deformationthe internal pressure of the skeleton member rises excessively and themember bends into a Z-shape or a dog-leg shape, and after that the loaddecreases sharply. Consequently, the absorbed energy is not that muchgreater than that of Comparison Example 1.

In Comparison Example 3 (small spheres bonded with adhesive, describedwith reference to FIG. 14), for the same reason as in Comparison Example2, the average load is large but the displacement λ is not that large,and the absorbed energy is not much greater than that of ComparisonExample 1.

In Comparison Example 4 (low-strength granules), because the granulesthemselves break up easily and the rise in the internal pressure of theskeleton structure member is not that sharp and the member does not bendinto a Z-shape or a dog-leg shape, although the displacement λ isgreater than in Comparison Example 2 and Comparison Example 3, becausethe granules remain inside the skeleton structure member, thedisplacement λ is smaller than in Comparison Example 1. Also, theaverage load is small, and as a result the absorbed energy is small.

From the foregoing results, it can be seen that it is difficult to raisethe average load of a skeleton structure member and simultaneouslyextend its effective stroke.

With the skeleton structure member 220 shown in FIG. 15, because it isfilled with the gel 223, when a load acts on the skeleton structuremember 220, the gel 223 flows smoothly and spurts out through theorifice, and consequently the internal pressure of the skeletonstructure member 220 is kept roughly constant during the deformation. Asa result, local deformation does not arise, and a relatively large loadcan be maintained up to a large displacement.

However, when the skeleton structure member is filled with granules,because due to frictional forces between the granules the fluid motionof the granules is not as smooth as the fluid motion of the gel 223, itis difficult to keep the internal pressure constant.

This will now be explained in detail with reference to FIG. 18 to FIG.20.

FIG. 18 shows deformation of a skeleton structure member having onedrain hole for granules to discharge through like the skeleton structuremember 220 shown in FIG. 15.

As shown in FIG. 18A, this skeleton structure member 240 is made up of askeleton member 241, multiple granules 242 packed inside this skeletonmember 241, and a cap 244 plugging a drain hole 243 formed in theskeleton member 241 to allow the egress of these granules 242.

As shown in FIG. 18B, a compressive load F is applied to the skeletonstructure member 240 in its length direction as shown with an arrow. Asa result, the internal pressure of the skeleton member 241 increasessharply, and the granules 242 push out the cap 244 shown in FIG. 18A andspurt out to outside through the drain hole 243.

As illustrated in FIG. 18C, the internal pressure of the granules 242 inthe vicinity where the granules 242 have spurted out falls, the strengthof the part near the drain hole 243 of the skeleton structure member 240decreases, and the whole member bends about this part. As a result, theload supported by the skeleton structure member 240 becomes very small.Consequently, the energy absorbed by the skeleton structure member 240is small.

FIG. 19 shows deformation of a skeleton structure member having aplurality of drain holes like that shown in FIG. 18.

The skeleton structure member 250 shown in FIG. 19A is made up of askeleton member 251, multiple granules 242 packed into this skeletonmember 251, and caps 254, 256 plugging a plurality of drain holes 252,253 formed in the skeleton member 251 to allow the granules 242 to flowout.

As shown in FIG. 19B, a compressive load F is applied to the skeletonstructure member 250 in its length direction as shown with an arrow. Asa result, the internal pressure of the top of the skeleton member 251increases sharply and the granules 242 push out the upper cap 254 shownin FIG. 19A and spurt out to outside through the drain hole 252.

As shown in FIG. 19C, the internal pressure of the granules 242 in thevicinity where the granules 242 spurted out falls, the strength of thepart of the skeleton structure member 250 near the drain hole 252decreases, and the whole member bends about this part.

When the load F is increased further, the internal pressure of thebottom of the skeleton structure member 251 increases and the granules242 push out the lower cap 256 shown in FIG. 19B and spurt out tooutside through the drain hole 253, and consequently the skeletonstructure member 250 bends about the part around the drain hole 253 asshown in FIG. 19D.

Because bending occurs at the part near the drain hole 253 and the wholemember folds like this, the load fluctuates markedly and as a result theabsorbed energy does not increase.

FIG. 20 is a graph showing crush test results of the skeleton structuremembers 240, 250 shown in FIG. 18 and FIG. 19.

In the case of Comparison Example 5 (the skeleton structure member 240),which has one drain hole, the load F is small and the maximum value ofthe displacement λ is also small, and consequently the absorbed energyis low.

In the case of Comparison Example 6 (the skeleton structure member 250),which has a drain hole in each of a plurality of locations, the memberdisplaced to a relatively large displacement d2 with the load Ffluctuating greatly.

The numeral f2 in the graph is the average load of Comparison Example 6,and because this is not that large, the absorbed energy is also not thatgreat as a result.

Accordingly, technology for increasing the energy absorbed by a skeletonstructure member for use in a transport machine has been awaited.

DISCLOSURE OF THE INVENTION

This invention provides a skeleton structure member for use in atransport machine made by filling a space inside a skeleton member of atransport machine and/or a space bounded by a skeleton member and apanel member peripheral to it with multiple granules, characterized inthat to suppress excessive rising of the internal pressure of the spacewhen that internal pressure increases, a granule flow allowing part intowhich the multiple granules can move is provided close to the granules.

Because a granule flow allowing part into which the granules can movewhen the internal pressure of the skeleton member increases is providedin the vicinity of the granules like this, even when a load acts on theskeleton structure member from outside and the internal pressure of thespace filled with the granules increases, along with that increase inpressure the granules move into the granule flow allowing part.Consequently, the internal pressure of the space does not riseexcessively, local deformation such as the skeleton structure memberfolding can be prevented from occurring, and it is possible to support alarge load through a large displacement. As a result, the energyabsorbed by a skeleton structure member according to the invention isgreater.

The granule flow allowing part of the invention preferably is providedinside the skeleton member and is formed as a cavity forming memberhaving a cavity. In one preferred embodiment, this cavity forming memberhas a cross-sectional closed space. The cavity forming member may be amember having a bellows shape. Also, the cavity forming member may be amember having a wall part that widens from an end at which a load actson the skeleton structure member to another end.

Also, the granule flow allowing part of the invention may consist of afoam material provided inside the skeleton member or may consist ofgranules less strong than the multiple granules mentioned above.

Also, the granule flow allowing part may be made up of a plurality ofallowing parts of different lengths provided inside the skeleton member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a skeleton structure member according toa first embodiment of the invention;

FIG. 2 is a sectional view on the line 2-2 in FIG. 1;

FIG. 3 is a sectional view on the line 3-3 in FIG. 1;

FIG. 4A, FIG. 4B and FIG. 4C are views showing deformation taking placeduring a crush test of a skeleton structure member according to thefirst embodiment;

FIG. 5A and FIG. 5B are views comparing a comparison example and apreferred embodiment to illustrate a principle of deformation of askeleton structure member according to the first embodiment;

FIG. 6 is a graph showing a relationship between load and displacementin a crush test on a skeleton structure member according to the firstembodiment;

FIG. 7A is a view showing the construction of a skeleton structuremember according to a second embodiment of the invention, FIG. 7B andFIG. 7C are views illustrating crush tests, and FIG. 7D is a graphshowing a relationship between load and displacement during deformation;

FIG. 8A and FIG. 8B are sectional views showing a skeleton structuremember according to a third embodiment of the invention and an exampleof deformation thereof,

FIG. 9A and FIG. 9B are sectional views of a skeleton structure memberaccording to a fourth embodiment of the invention;

FIG. 10A and FIG. 10B are sectional views showing a skeleton structuremember according to a fifth embodiment of the invention and an exampleof deformation thereof;

FIG. 11 is a sectional view showing a skeleton structure memberaccording to a sixth embodiment of the invention;

FIG. 12A and FIG. 12B are sectional views showing a skeleton structuremember according to a seventh embodiment of the invention and an exampleof deformation thereof;

FIG. 13 is a sectional view showing a first skeleton structure member ofrelated art;

FIG. 14 is a sectional view showing a second skeleton structure memberof related art;

FIG. 15 is a sectional view showing a third skeleton structure member ofrelated art;

FIG. 16 is a view showing deformation of a skeleton structure member ofrelated art;

FIG. 17 is a graph showing a relationship between load and displacementof when the skeleton structure member shown in FIG. 16 deforms;

FIG. 18 is a view showing deformation taking place when one drain holefor granules to flow through is formed in a skeleton structure member;

FIG. 19 is a view showing deformation taking place when a plurality ofdrain holes for granules to flow through are formed in a skeletonstructure member; and

FIG. 20 is a graph showing a relationship between load and displacementof when the skeleton structure members shown in FIG. 18 and FIG. 19 arecrushed.

BEST MODES FOR CARRYING OUT THE INVENTION

FIG. 1, FIG. 2 and FIG. 3 show a skeleton structure member according toa first embodiment of the invention. As shown in FIG. 1, a skeletonstructure member 12 for a transport machine according to a firstembodiment (hereinafter written “skeleton structure member 12”) has astructure wherein a hollow skeleton member 11 is filled with multiplegranules. The reference numbers 13, 13 denote end closing members forclosing the ends of the skeleton member 11.

As shown in FIG. 2, the skeleton structure member 12 is made up of theskeleton member 11 having a space 16 filled with multiple granules 17,and a granule flow allowing part 14 disposed inside the skeleton member11.

This granule flow allowing part 14, in the first embodiment, consists ofa cavity forming member 15. The cavity forming member 15 has a cavity18.

As shown in FIG. 3, the skeleton member 11 is made up of twocross-sectionally U-shaped skeleton halves 21, 21 and flanges 21 a, 21 aformed integrally with the edges of the same. The two skeleton halves21, 21 are brought face-to-face so as to form a cross-sectionally closedspace and joined together with the cavity forming member 15 by theflanges 21 a, 21 a.

The cavity forming member 15 is made up of two cross-sectionallyU-shaped forming member halves 22, 22 and flanges 22 a, 22 a formedintegrally with the edges of the same. The two forming member halves 22,22 are brought face-to-face so as to form a cross-sectionally closedspace and joined to the flanges 21 a, 21 a of the skeleton halves 21, 21by the flanges 22 a, 22 a.

The forming member halves 22 are members lower in strength than theskeleton halves 21, made easier to deform by for example being madesmaller in plate thickness.

FIG. 4A to FIG. 4C show deformation of a skeleton structure memberaccording to the first embodiment during a crush test.

As shown in FIG. 4A, a load F is applied as a compressive load to theskeleton structure member 12 in its axial length direction. The strokeof a pressing member (not shown) for applying the load at this time,that is, the downward displacement of the pressing member, will bewritten λ.

As shown in FIG. 4B, when the load F acts on the skeleton structuremember 12, an internal pressure arises in the upper part of the space 16of the skeleton structure member 12 filled with the granules 17. This isbecause the granules 17 are packed tightly in the space 16.

As shown in FIG. 4C, when the skeleton structure member 12 displaces bya displacement λ, the load in the direction perpendicular to thedirection in which the load F is applied becomes large, and as shownwith arrows the granules 17 push on the cavity forming member 15 anddeform the upper part of the forming member 15 to the inside, i.e. tothe cavity 18 side, and the granules 17 move toward the cavity 18 side.Although not as much as the cavity forming member 15, the skeletonmember 11 also deforms, to the outside.

Consequently, because the internal pressure of the space 16 does notrise excessively and a predetermined internal pressure is approximatelymaintained, the cavity forming member 15 and the skeleton member 11 donot deform locally, and do not bend.

After that, the part where the internal pressure is high gradually movesdown the skeleton structure member 12, and the skeleton member 11 andthe cavity forming member 15 continue deforming as discussed above andabsorbing energy.

If the load acting from outside is large and the internal pressure inthe space 16 increases further, the cavity forming member 15 breaks, forexample by cracks arising in the cavity forming member 15, and throughthese cracks the granules 17 flow into the cavity 18, preventingexcessive rising of the internal pressure of the space 16.

FIG. 5A and FIG. 5B show the skeleton structure member of the firstembodiment in contrast with a comparison example, to illustrate aprinciple of its deformation.

FIG. 5A is the comparison example, and shows a skeleton structure member263 with a space 262 filled with granules 261 and a relationship betweenthe granule pressure P (this is the pressure acting on the granules 261in the direction perpendicular to the direction of the axial compressiveload F when the axial compressive load F is applied to the skeletonstructure member 263, and is the internal pressure of the space 262) andthe distance L (the distance from the top end position of the space 262to the bottom end position).

When the axial compressive load F is applied to the skeleton structuremember 263 of the comparison example, the internal pressure of the space262 increases. That is, if the point at which the load F is applied tothe skeleton structure member 263 is called the load application point264, the pressure P of the granules 261 near this load application point264 is extremely large, and as the distance L increases the granulepressure P decreases. This is because unlike a gas or a liquid, in thegranules 261, large frictional forces arise between adjacent granules261 and between the granules 261 and the wall faces of the skeletonstructure member 263, and the granule pressure P is not uniform insidethe skeleton structure member 263 and falls rapidly with progress awayfrom the load application point 264.

With respect to this, in this embodiment, as shown in FIG. 5B, when anaxial compressive load F is applied to the skeleton structure member 12,because the cavity forming member 15 deforms to the cavity 18 side asshown with arrows, the granule pressure P does not rise excessively, andthe maximum granule pressure p2 arising in the end of the space 16 nearthe load application point 24 is lower by Δp than the maximum granulepressure p1 of the comparison example. That is, although the granulepressure P decreases as the distance L increases, it tends more to beconstant than in the comparison example.

By providing a low-rigidity part or a brittle part like the cavityforming member 15 and a cavity 18 for allowing deformation of the cavityforming part 15, that is, a cavity 18 into which the walls of the cavityforming member 15 and the granules 17 can move (a cavity 18 into whichthe granules 17 flow when the cavity forming member 15 has broken) inthe forming member 15 in the skeleton structure member 12 like this, itis possible to prevent excessive pressure rise inside the space 16 whenthe granule pressure P tends to rise.

FIG. 6 is a graph showing the relationship between the load F and thedisplacement λ of when a crush test on the skeleton structure member ofthe first embodiment was carried out.

In the first embodiment, wherein a cavity (enterable space) into whichgranules can move is provided, if the average load is written f3, thisaverage load f3 is greater than the average load f2 of ComparisonExample 6 (with drain holes in a plurality of locations), andfurthermore because the maximum displacement λ of the first embodimentis large, i.e. the effective stroke is large, compared to the comparisonexamples the absorbed energy can be made larger.

In this embodiment, as shown in FIG. 3, a square member forming across-sectionally closed space by two cross-sectionally U-shaped halvesbeing brought together was shown as the skeleton member 11; however, theinvention is not limited to this, and for example a closed space may beformed with a skeleton member having a cross-sectionally U-shaped openpart and a panel member around the skeleton member, closing off the openpart. That is, in this invention, multiple granules are packed into aspace inside a skeleton member and/or a space bounded by a skeletonmember and a panel member peripheral to it.

As explained with reference to FIG. 5A and FIG. 5B, the invention is askeleton structure member 12 wherein a space inside a skeleton member 11of a transport machine and/or a space bounded by a skeleton member 11and a panel member peripheral to it is filled with multiple granules 17,and has the characteristic feature that excessive rising of the internalpressure of the space 16 is suppressed by a granule flow allowing part14 into which the granules 17 can flow when the internal pressure of thespace 16 has increased being provided near the granules 17 in the space16.

As a result of a cavity 18 into which the granules 17 can move when theinternal pressure of the space 16 has increased being provided in thevicinity of the space 16, for example when an axial compressive loadacts on the skeleton structure member 12 from outside, even if theinternal pressure of the space 16 filled with granules 17 increases,because along with that increase in pressure the granules 17 flow to thecavity 18 side, the internal pressure of the space 16 does not riseexcessively, local deformation such as the skeleton structure member 12folding can be prevented, a large load can be supported through a largedisplacement, and compared to related art it is possible to increase theamount of energy absorbed by the skeleton structure member 12.

Therefore, it is possible to absorb for example the impact energy of avehicle collision with the skeleton structure member 12 effectively.

FIG. 7A to FIG. 7D show a skeleton structure member according to asecond embodiment of the invention, and a crush test.

FIG. 7A shows a skeleton structure member 35 wherein a cavity formingmember 32, which is a granule flow allowing part 14, is fitted inside askeleton member 31, multiple granules 17 are packed in a space 33between the skeleton member 31 and the cavity forming member 32, and acavity 34 is provided in the cavity forming member 32.

In FIG. 7B, an axial compressive load F is applied to the skeletonmember 31 on its own and the skeleton member 31 is thereby forciblydeformed. λ is the displacement.

In FIG. 7C, an axial compressive load F is applied to the cavity formingmember 32 on its own and the cavity forming member 32 is therebyforcibly deformed.

FIG. 7D is a graph showing the relationships between the loads F and thedisplacements λ in the deformations of FIG. 7B and FIG. 7C.

The solid line in the graph is the result for the skeleton member andthe dashed line is that for the cavity forming member. For example whenthe displacement λ at which the second peak (maximum value) of the loadF on the skeleton member arises is written d5 and the wavelength of theskeleton member load is written W, if setting is carried out so as tostagger the phases so that the displacement λ at which the second peak(maximum value) of the load F on the cavity forming member lies at thedisplacement d6, W/2 larger than the displacement d5 of the skeletonmember, then when the load on the skeleton member and the load on thecavity forming member are applied, the relationship between the load Fand the displacement λ shown with the broken line is obtained. That is,this line is the characteristic of the skeleton structure member 35 ofthe second embodiment as shown FIG. 7A, and the load fluctuation issmall.

As means for providing this phase difference, there are (1) the methodof making the cross-sectional dimensions of the cavity forming member ½of those of the skeleton member, (2) the method of providing beads(layers of weld metal) or notches (V-shaped cuts) in the cavity formingmember, and (3) the method of assembling the skeleton member and thecavity forming member with their respective leading ends (the ends onwhich the load acts) staggered.

FIG. 8A and FIG. 8B show a skeleton structure member according to athird embodiment.

The skeleton structure member 40 of the third embodiment shown in FIG.8A is made up of a skeleton member 11 and a granule flow allowing part42 provided inside this skeleton member 11. Multiple granules 17 arepacked in a space 43 between the skeleton member 11 and the granule flowallowing part 42, that is, the space 43 of the skeleton member 11. Thegranule flow allowing part 42 consists of a foam member 45.

The foam member 45 is made of polyurethane or foamed aluminum or thelike. The foam member 45 is received in a for example filmlike receivingmember.

When an axial compressive force is applied to the skeleton structuremember 40, the internal pressure of the space 43 increases and thegranules 17 push on the side walls of the foam member 45, and againstthe reaction force of the foam member 45 cause the wall faces of thefoam member 45 to deform inwardly. As a result, the internal pressure ofthe space 43 remains substantially constant.

If the axial compressive load acting on the skeleton structure member 40at this time increases, the internal pressure of the space 43 increasesfurther, cracks arise in the wall faces of the foam member 45, granules17 flow into the foam member 45 through the cracks, and excessivepressure rise inside the space 43 is prevented.

The skeleton structure member 50 shown in FIG. 8B is a variation on theskeleton structure member 40 shown in FIG. 8A, and is made up of askeleton member 11 and a granule flow allowing part 42 provided insidethis skeleton member 11. Granules 17 are packed between the skeletonmember 11 and the granule flow allowing part 42. The granule flowallowing part 42 is made of hollow granules 51.

The hollow granules 51 are for example made by heating so-calledmicrocapsules, made by atomizing a core substance consisting of alow-melting-point hydrocarbon (liquid or solid) and covering this coresubstance with a thermoplastic resin film (that is, wrapping it with ashell), to gasify the core substance and soften and inflate the film(the shell). The hollow granules 51 are packed in a for example filmlikereceiving member.

When an axial compressive load is applied to the skeleton structuremember 50, the internal pressure of the space 43 increases and thegranules 17 push on the wall faces of the granule flow allowing part 42and against the resistance of the hollow granules 51 deform the wallfaces of the granule flow allowing part 42 inwardly.

At this time, by adjusting the amount of uninflated microcapsules firstpacked into the granule flow allowing part 42, it is possible to adjustthe internal pressure of the granule flow allowing part 42 after themicrocapsules are heated and inflate. Accordingly, the reaction force ofthe hollow granules 51 against the pushing force of the granules 17 ischangeable, and it is possible to adjust the internal pressure of thespace 43.

If the granule flow allowing part 42 is filled with granules that aremore easily compressed than the granules 17 like this, when the internalpressure of the space 43 rises, the wall faces of the granule flowallowing part 42 are deformed to the side of the easily compressedgranules.

FIG. 9A and FIG. 9B show a skeleton structure member according to afourth embodiment of the invention.

In FIG. 9A, the skeleton structure member 60 of this fourth embodimentis made up of a skeleton member 11 having multiple granules 17 packed ina space 63, and a granule flow allowing part 61 provided inside thisskeleton member 11. The granule flow allowing part 61 of this embodimentconsists of a cavity forming member 62 that is bellows-shaped invertical cross-section. This cavity forming member 62 has a cavity 64.

The cavity forming member 62 is a member that is pre-formed into theshape of a periodic wave (that is, the same waveform repeatedcyclically) like the deformation that occurs when an axial compressiveload is applied.

When an axial compressive load F is applied to the skeleton structuremember 60, the internal pressure of the space 63 increases, and as shownin FIG. 9B, when the displacement reaches λ2, the granules 17 push onthe wall faces of the cavity forming member 62. Because thebellows-shaped cavity forming member 62 has been formed in a periodicwave of deformation, the wall faces of the cavity forming member 62smoothly deform into the cavity 64 so as to increase the amplitude ofthe periodic wave.

Along with this, the skeleton member 11 also deforms to substantiallythe same shape as the bellows-shaped cavity forming member 62. As aresult, during the deformation of the skeleton structure member 60 thepressure of the granules 17 is kept approximately constant, fluctuationof the load is also small, a large load is maintained through a largedisplacement, and the energy absorbed by the skeleton structure member60 increases.

FIG. 10A and FIG. 10B show a skeleton structure member according to afifth embodiment of the invention.

The skeleton structure member 70 of the fifth embodiment shown in FIG.10A is made up of a skeleton member 11 having multiple granules 17packed in a space 73, and a granule flow allowing part 71 providedinside this skeleton member 11. The granule flow allowing part 71consists of a cavity forming member 72 having a cavity 74. The cavityforming member 72 is tapered in vertical cross-section.

Here, if the end closing members 13, 13 of the skeleton member 11 shownin FIG. 2 are called the end closing member 13 a on which the load ismade to act and the other end closing member 13 b, then the taperedcavity forming member 72 has tapering walls 76, 76 that widen from theend closing member 13 a toward the end closing member 13 b.

Because as explained with reference to FIG. 5B the granule pressure Pfalls with progress away from the load application point 24, in FIG.10A, for example when an axial compressive load is applied to the endclosing member 13a, the internal pressure of the space 73 graduallybecomes smaller with progress from the end closing member 13 a endtoward the end closing member 13 b end. Accordingly, if the horizontalcross-sectional area of the space 73 packed with the granules 17 is madeto gradually decrease from the end closing member 13 a toward the endclosing member 13 b, the internal pressure of the space 73, that is, thepressure among the granules 17 (i.e. the granule pressure) can be keptconstant.

The skeleton structure member 80 shown in FIG. 10B is a variation of theskeleton structure member 70 of the fifth embodiment shown in FIG. 10A.This skeleton structure member 80 is made up of a skeleton member 11with a tapering vertical cross-section, and a granule flow allowing part81 provided inside this skeleton member 11. Multiple granules 17 arepacked in a space 83 in the skeleton structure member 80. The granuleflow allowing part 81 consists of a cavity forming member 82 havinginside it a cavity 84.

The skeleton member 11 has end closing members 86, 87 at its ends, andhas tapering walls 88, 88 formed so as to narrow with progress from theend closing member 86, at the end to which the load is applied, towardthe other end closing member 87. The pressure acting inside thisskeleton structure member 80 is the same as in the skeleton structuremember 70 shown in FIG. 10A.

FIG. 11 shows a skeleton structure member according to a sixthembodiment of the invention.

This skeleton structure member 90 is made up of an skeleton member 11having a space 93 packed with multiple granules 17, and a granule flowallowing part 92 provided inside this skeleton member 11.

The granule flow allowing part 92 is made up of a central first allowingpart 95, second allowing parts 96, 96 disposed on either side of thefirst allowing part 95, and third allowing parts 97, 97 disposed on theouter sides of the second allowing parts 96, 96, of different lengthsand disposed in the length direction of the skeleton member 11.

The first allowing part 95, the second allowing parts 96, 96 and thethird allowing parts 97, 97 are spaces formed example with membranemembers or films.

When the end closing members 13, 13 of the skeleton member 11 are calledthe end closing member 13 a on which the load is made to act and theother end closing member 13 b, then the positions of the ends of thefirst allowing part 95, the second allowing parts 96, 96 and the thirdallowing parts 97, 97 are aligned at the end closing member 13 b end.

If the respective lengths of the first allowing part 95, the secondallowing parts 96, 96 and the third allowing parts 97, 97 are writtenL1, L2 and L3, then L1>L2>L3, and their horizontal cross-sectional areasare the same.

For example when an axial compressive load is applied to the end closingmember 13 a, because the internal pressure of the space 93 graduallydecreases from the end closing member 13 a toward the end closing member13 b, as a result of the horizontal cross-sectional area of the space 93filled with the granules 17 being made to decrease in steps from the endclosing member 13 a end toward the end closing member 13 b end by themultiple allowing parts 95, 96, 96, 97, 97 being provided, the internalpressure of the space 93, i.e. the pressure acting among the granules17, becomes approximately constant.

FIG. 12A and FIG. 12B show skeleton structure members according to aseventh embodiment.

The skeleton structure member 110 of the seventh embodiment shown inFIG. 12A is made up of a skeleton member 11 and a granule-filled member112 provided inside this skeleton member 11. The granule-filled member112 has a closed space 113 bounded by a cross-sectionally rectangularwall part 112 a, and the closed space 113 is filled with multiplegranules 17.

Between the skeleton member 11 and the granule-filled member 112 isformed a granule flow allowing part 114 consisting of a space.

When an axial compressive load acts on the skeleton structure member110, because the multiple granules 17 are packed tightly in the closedspace 113 of the granule-filled member 112, the internal pressure of thegranule-filled member 112 rises. Then, the granules 17 push on the wallpart 112 a of the granule-filled member 112 and deform and break thewall part 112 a outward, i.e. toward the granule flow allowing part 114consisting of a space, and the granules 17 flow into the granule flowallowing part 114. As a result, the internal pressure of the skeletonstructure member 110 as a whole is kept constant, and its absorbedenergy increases.

The skeleton structure member 120 shown in FIG. 12B is a variation ofthe skeleton structure member 110 of the seventh embodiment shown inFIG. 12A.

This variant skeleton structure member 120 is made up of a skeletonmember 11 and a granule-filled member 122 provided inside this skeletonmember 11. This granule-filled member 122 has a closed space 123 boundedby a cross-sectionally cross-shaped wall part 122a with four cornerparts cut away, and the inside of the closed space 123 is filled withmultiple granules 17.

Between the skeleton member 11 and the granule-filled member 122, inother words in the four corner parts where the granule-filled member 122is cut away, granule flow allowing parts 124 consisting of spaces areformed.

The effect of this skeleton structure member 120 is the same as theeffect of the skeleton structure member 110 shown in FIG. 12A.

Although in this embodiment, (1) an example was shown wherein a spacebounded by a skeleton member and a granule flow allowing part, or aspace inside a granule-filled member, is filled with granules, theinvention is not limited to this, and alternatively (2) a space boundedby a skeleton member and a panel member around that may be filled withgranules, or spaces (1) and (2) may both be filled with granules.

INDUSTRIAL APPLICABILITY

Because the skeleton structure member of this invention increases theenergy absorbed by a skeleton structure member, it is suited to skeletonstructure members used in transport machines such as railroad cars,industrial vehicles, ships, aircraft, automobiles and motorcycles.

1. A skeleton structure member for use in a transport machine havingmultiple granules packed in a space inside a skeleton member of atransport machine and/or a space bounded by a skeleton member and apanel member around the skeleton member, wherein, to suppress excessiverising of an internal pressure in the space during increase of theinternal pressure, a granule flow allowing part, into which the multiplegranules can move, is provided close to the granules.
 2. The skeletonstructure member according to claim 1, wherein the granule flow allowingpart is provided inside the skeleton member and comprises a cavityforming member that defines a cavity.
 3. The skeleton structure memberaccording to claim 2, wherein the cavity forming member isbellows-shaped.
 4. The skeleton structure member according to claim 2,wherein the cavity forming member has a wall part having a first end atwhich a load acts on the skeleton structure and a second end opposite tothe first end, and wherein the cavity forming member wall part widensfrom the first end to the second end.
 5. The skeleton structure memberaccording to claim 1, wherein the granule flow allowing part comprises afoam member that is provided inside the skeleton member.
 6. The skeletonstructure member according to claim 1, wherein the granule flow allowingpart comprises granules provided inside the skeleton member and whereinsaid granules provided inside the skeleton member are weaker in strengththan said multiple granules.
 7. The skeleton structure member accordingto claim 1, wherein the granule flow allowing part comprises multiplegranule flow allowing parts of different lengths, said multiple granuleflow allowing parts being provided inside the skeleton member.